title: GDNF signaling levels control migration and neuronal differentiation of enteric ganglion precursors.
abstract: Pleiotropic growth factors play a number of critical roles in continuous processes of embryonic development; however, the mechanisms by which a single regulatory factor is able to orchestrate diverse developmental events remain imperfectly understood. In the development of the enteric nervous system (ENS), myenteric ganglia (MGs) form initially, after which the submucosal ganglia (SMGs) develop by radial inward migration of immature ENS precursors from the myenteric layer. Here, we demonstrate that glial cell line-derived neurotrophic factor (GDNF) is essential for the formation not only of the MGs, but the SMGs as well, establishing GDNF as a long-term acting neurotrophic factor for ENS development in a mouse model. GDNF promotes radial migration of SMG precursors. Interestingly, premigratory SMG precursors in the myenteric layer were distinguished from the surrounding neuronally differentiating cells by their lower activation of the GDNF-mediated MAPK pathway, suggesting that low activation of GDNF downstream pathways is required for the maintenance of the immature state. ENS precursors devoid of GDNF signaling during midgestation halt their migration, survive, and remain in an undifferentiated state over the long-term in vivo. Reactivation of GDNF signaling in these dormant precursors restores their migration and neuronal differentiation in gut organ culture. These findings suggest that pleiotropic function of GDNF is at least in part governed by modulating levels of intracellular activation of GDNF downstream pathways; high activation triggers neuronal differentiation, whereas low activation is crucial for the maintenance of progenitor state.
authors.affiliation: Laboratory for Neuronal Differentiation and Regeneration, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan, Department of Development and Regeneration, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan, and Division of Neural Differentiation and Regeneration, Department of Physiology and Cell Biology, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Uesaka
authors.forename: Mayumi
authors.initials: M
authors.lastname: Nagashimada
authors.forename: Hideki
authors.initials: H
authors.lastname: Enomoto
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement; D017615:Enteric Nervous System / Q000196:embryology*; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000378:metabolism*; D007150:Immunohistochemistry; D051379:Mice; D008817:Mice, Mutant Strains; D058953:Neural Stem Cells / Q000166:cytology* / Q000378:metabolism; D055495:Neurogenesis; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D051100:Glial Cell Line-Derived Neurotrophic Factor